Automatic train-control system.



R. C. LEAKE.

AUTOMATIC TRAIN CONTROL SYSTEM.

APPLICATION FILED JULY 23, I915.

1,291,565, Patented Jan. 14,1919.

INVENTOR A g A WJM 7 Specification 0t 3pc 'iii in his i inniicnliy ccn'ti'ciiing 'aiiwa-y in "11s and more pzu'ticiflaii'l to such systems in rvhici'i the movement of the twin is contrclimLin some appropriate, Way, by accd coma-01 nip pnrntns and :mfinnntic stop mechanism cm:- ri'cd cn. thc mii 1 the control of mid spccd cc ntrcl appnmins and said stop mechanism 1" a c-mini when incwhiinicaiiy and clcc" cccpcmtion of IL contm-c s'nce cc :3: cried by inc train. and an. dcvicib located along the principni objects of the invcnan rangcn'icnt of circuits me rmnps along tnc track- .30 as "[Uflmfli'fiiilifl these many in the cninc condi "in a train pziz rscs them, wherein the c n1 vliicicncy m the syi-stcin Qn incfibc nflccicn if more than cnc vci'iicic, n ion-Quin{xiva mn maimcni'. cquip 'icd 51c mitomniic t'z'ziin IOMTK'Oi npinn'nins nicci in n inn.

: ci'ncc 'g of the invention. to and i'chu'nic "rain cmmoi humus zninps :icng the tmckway, they with cn'cnns and. cicctcicnl connecmy iions fiiwitcfin which will ccns'tii-nic m'icqnatc incnns for ccnti'cil ngz $110 1112 1cm; of tho min iwi'n Ifilfiiii conditimis which require win in imam- 1 cnuticnsiy and nmici? which .i'cquiizc inc 'i'x'nin to be to {m niasoiuic sing). ti innobi sci oi Um ini'c'niicn into dcainxinm'i system for controlling twins for n block systcin in which "urination fur fin: pircpcl control f 1c trains inny be (LliEIlSll'liLtEKi from one flock no :iimthc and .ciwt amount of. my i'ict'wecl'is id Mocks.

Other obj 001s and ac'ivnntngcs will appear 1110 iiicucrip'ricn of dc invention pr0- Winch will require flic niltins and hnc wl'ccs Applica'iicn filed July 183, 1315. EJ'c'ciaI'Z'e'n. (a1,

, providing a sections, and. which ncc pm'ticnlni'ly painted out in the:

trance "5-0 each block section cf c to which is comicciicd and by tmhcu suitzibic cic 11cm npphn the condition. of inc rump m: can adjacent to each control scction n'i. mined the smnc \vhiic a train is conm'rf. sccfiicn.

Thc im'cntlon fnrthcr consist; in in ramp for ouch clock sccticn. 'iwkvuy Winch it, (,cnnccccd 2;; bin tricnl appliances Wiiic i arc 11 p011 iv t1) prcsci'icc 1 E trains in ccianin 01" said iii cans-a lii'fcrcni; 1i cc'niiiticns "to exist for each min}: (him: "to izhc prescncc of trains on cc "3 block Sccmcnc; wind in ni'khcr prov. I 355 sniinb lc train control apparatus cm. [:hc train which ccsponsivc to him nicc (:OndiiiiOllQ 0'? said ramps.

Th s invention. illlfiixkd ccnsim and in the ari'nngcincnts and cc of panic, mznc 11113; sci: ici'ilh i:

In d

il'CD'IZU I living, 8%) 'WQQQciIl .111: Mint-c. n picfcrrcd physicai ci'nbcflinicnt cf any iLJVciiiizJn, and n'bcrcin likc cinn'ncizcrs cf i'cfc 'cncc Czcsigp nntc corresponding psi-in iiwnxghcnt 31c scvcmi views, and in which:

The Egan-c is n dingvnmznntic ilimtrnivicn of a railway train or vehicle and. :2 "1': said train, and siicws; "(in-i warn-3 11mm train ccnn'ol systcni 1 ingvcntimn both those pin-h:v mated. with the ham" and tncse wiicn located along the t'nc1 tcggciihcr with cuits cnil cicctrica] qcnnccticns bctwnen parts. the c icrniivv parts being shown m said figni-c in izhcir normal positions ms. in M {he condition existing; whcn a train n11)- and when traffic conditions permit said train to proceed at uni-estrictcd. speed.

Referring to H18 accompanying draining in; one track mi] of the, railway track is 01cctrically continncn i, the scpnmic mil secticns length desired to obtain the the train passes of wheels of said train will at all times be thereof being suitably bonded together; and the other track rail 2 is divided into electrically distinct sections A, B, C, D, and E in any suitable way, as by insulating joints The sections A, C and E may be of any required spacing of the trains, and for convenience in description will be hereinafter termed block sections. The sections B and D are comparatively short and may be as short as desired, providing that they are longer than the distance between any two successive pairs of wheels. In other words, the sections B and D, which will be hereinafter termed control sections, are long enough so that as over them at least one pair on said control section. Although only two control sections B and D, the intermediate block section C and the adjacent ends of the two block sections A andE are shown in the drawings, it is to be understood that the same alternate arrangement tions and block sections is carried out throughout the desired length of the track, a control section being located at the entrance to each block section, as illustrated, the direction of normal traflic being indicated by the arrow Extending along the track are two line wires 4 and 5, WhlCh are supported in any suitable manner, as on poles'according to the usual construction; and these line Wires 4; and 5 are electrically connected to a source of alternating current, as a generator 6. The. parts and the circuits are the same for the control sections B and D, and the parts and conductors associated with the control section D are given the same reference characters as the corresponding parts and conductors of the control section B with a distinctive exponent 1 added thereto. Adjacent to one end of each block section is a track transformer' 7, the secondary of which To block section a track relay 10 is connected across the trackralls 1 and 2, said track relay 10 being of any suitable construction which will make said track relay responsive to alternating cur- The track relays 10, together with the track rails 1 and 2 and the track transformers 7 of each block section constitute the well known normally closed track circuit, as will be clearly understood by those skilled in the art of railway signaling. Normally, that is, when no train occupies a locksection, the track relay 1-0 of that block section is energized and the armatures 11, 12, 13 and 14 of said track relay will be in their upper position as shown in the drawing.

Associated with each control relay L. hereinafter termed a section is a ramp relay.

/ currents.

of control sec-' menace The relay L is of the type commonly known in the art as a three-position alternating current relay, and is susceptible to alter: nating current, although immune to direct This.relay is illustrated according to established convention; and, as will be understood by those skilled in the art of alternating current railway signaling, comprises a rotor (not, shown) which is operatively connectd to the arm'atures l7, 18, 19 of the relay and which, when the two coils 15 and 16 of said relay are energized by alternating current, will move said armatures in. one direction or the other from their neutral position, shown in the drawing, according to the way in which said coils l5 and 16 are energized. The detail construction of this three-position ramp relay is not shown and described, since this type a and the lay which are essential to a clear understanding of this invention, will be pointed out hereinafter in the description of; the operation.

Adjacent to the entrance of each controlsection B and D is a contact rail or ramp R, which is supported in any suitable way, as on the ties by special supporting memers, ad acent to one ofthe track rails; but ramp R is insulated from said ties and from the track rails.

Associated with each control section B and D is a transformer 20 which is used as electrical energy to create either low difference of potential between the corresponding ramp and the track The primary of this transformer 20 is connected to the line wires rand 5 and its secondary is connected to conductors, hereinafter fully set forth, through the medium of which the above mentioned high and low conditions of potential are created. Also associated with each control section is another transformer 21, the primary which is connected to the-line wires 4 and 5' and the secondary of which is arranged to supply current to energize the coil 15 of the corresponding ramp relay L. Another transformer 22 is associated with each control section and is connected in a similar way to the line wires 4 and 5 and is usedto supply current to the coil '16 of the ramp relay L associated with the preceding control section. he conductors and electrical connections The railway train is cally as vcomprising 24-24 connected by shown diagramm at'itwo pairs of wheels he usual axles 25 and hereinafter 1n the description sumporting bar b'racimt 8 is suit- 0 326i on the brain, p'sofmrably beam (x1e m.- ji'mrnuf, box as am the bl'm kcin is or lunge? 31 Y a compres- 211-11171 0 the 'irzmk armnps-a'mi one of m D iLSSt-S it when umph f3, imam for uniiui'umstic n and arii'i'fifi. by the at thereof eiec'izro pneu- '0 lli'lhlfiffr n (4 15-2 iii.

m1, n'rin-nipgw in 00-11% a "brain whim the {Tail the maid.

be used w (011.71 1

' xhale, up

of the train iyv mining plicatien of ivrula; 4 (.m'iuo i: may I mint in ih than} of -the '01' speed of iii-e, has "i into 013 operate in apply t i "from the train and tviiedisbanca it t'mveieii after dexicc K was 7 a be "i I. 7 descrmed in. paiem Lu J J, Fymnuen, i [v -gust 11', 1915p i A ship devica ii i stow relay turn 46 in its upper energized when the an.

current stop rainy S which has two mumtums 3b and P3 in. Tim mrnniure Y Tim when in its upper M1i01'i, 0] s41 (:ircu i0? emergizing the device S in render it imzzpzi i 0i stopping the train,

mid circuit bein fellows:

Battery 38, wn Im-(ms 53% and -10, urinal-- lure 37 in UPPLJ position concluctm' 1, dvvizze :md conductors 4;) and 43 5 back '10 the but cry 38. i

The spvmi control device K is wni'milcd by :1 (iii-cc nun-(ant control rah-y iii inwmg two armatures is) and "W5. TVhi-n the zu'mzv fun? &3 of Um cont-1'01 why If in :19 upper position it closes; '21 circui'iv for supplying mur- L'Oiii' to the ievicc K to render it incapable of com-01131 the, movement oiithe train, sniii circuit being as follows:

I? Mar; 38, minimal 39 and 1 position, (in-nu device iii, and cmifiucfm's anti 23 thc 38.

hen Fno shoe 3-1 is-iin its imvm? 2L posii'mn, as; shown in the tir vlin g H w v "3. we shoe. 1.: 1104, m 0.: w 2

ramp, the siiop 11 S tub 00mm! Lay K am 110mm janergizzcii from :'\v incal source 01? vim-em cui'rfcci. by i'iic; mall mi 7 This nm'iinally closed (lirQct mil-"uni holding; circuifl 1%?01' The ship relay Mutiny 50, conductors Amend-rm: 35 (mum: siiiring g and 5% :u li lUQ 30 in i" m'tmduci'o' mi and 555 stop 2. (luciuna 5. 7 and 13* 4 fl'ujifmii "ii'w dix-eci cu 0110 in ding circuit for the 'itml min i? as; inflows:

Biiiitj, 50, calcium 1's 51 111d 552, 00111; c za'wmi'm- 553, UODLHJJJ" 1g 34-, 2nd fit) zu'znm'iii'e -16 in ifs upper positioi'i. com'hicimy 30 and (BL comm. i'o iuy K, and conductors 6:2 mid back to the b The PDBIgIiZntiOH -11 the amp P018) {)9 is also continued b;\' an armature (53 0'! the mlhn'nming (ifllimli, ":top rainy S, the s'top relay 5 being enmgtzzed \vi'wn said tL'lYim'i'Lfl'P (53 is in its-111mm pdsitikm. according to the following cil cuit i Battery 50, conductors .31, (ii and 65, a1- mature 63 in its upper position, conductmx's and 58 bm'i to Hm battery 50. I in a sim lar way the 001.!1'01 relay i conductors 53 50, stop relay S, and conductors 57 i nating current control relay K is in its upper position according to the following circuit:

I Circuit number six.

Circuit number seven.

From the shoe 31, conductors 70 and 71, relay S, and conductors 72 and 73 to the frame 28 of thetrain. m

The partial circuit in multiple with theabove-mentioned partial circuit for the alternating current control relay K is as follows:

Circuit number eight.

From the shoe 31, conductors 70 and 7 1, relay K, and conductors 7 5 and 73, to the frame 28 of the vehicle. 7

The purpose of this partial circuit and th effect produced by supplying alternating current to it will be more fully described hereinafter in the description of the opera- Having described generally the structure and arrangement of the various parts constituting the system for automatically controlling railway trains which embodies the invention, and in general the operation of the parts of this system which are mounted on the train, the operation of the system as a whole will be described for different cases in which certain conditions of trafiic, such as may occur in practice, are assumed to exist along the trackway.

For t e first condition of traffic to be considered, assume that the train under consideration is in the block section A and is about to enter the control section B, as shown in the drawing; that said train has found the trackway unobstructed and is running without being under the control of the speed control device K, and that neither the block section C or E are occupied by a train. Since the block sections C and E are not occupied, their respective track relays 10 and 10 are energized and the armatures of said track relays are in their upper positions, as shown in the drawing. Before the wheels of the train enter the control section B, the shoe 31 carried'by said train engages theramp R and in addition to making electrical contact with said ramp, said shoe is raised and presses the contact spring 34 out of contact with the contact member plied to said relays S D along a circuit as Circuit number nine.

From the ramp R, conductor 80, armature 12 of the track relay 10 in its upper position, conductors 81 and S2 to the secondary of the transformer 20, high voltage tap I: and conductor 83 to the track rail 1.

Consequently, when the shoe 31 makes electrical contact with the ramp R, current is supplied to the alternating current relays S and K, since the high difference of potential between the ramp R and the track rail, which is existent because of the partial circuit number nine, sends current through the partial circuits numbers seven and eight for said relays. In this way, although the direct current holding circuits numbers three and four for the stop relay S and the control relay K are broken by the raising of the shoe 31, current is simultaneously supand K by reason of the fact that the alternating current relays S and K are energized and their respective armatures 63 and 67 are raised to close the A circuits numbers five and six for energizing: said relays S and Ki and this condition exists until the first pair of wheels 24 .24 enter the control section B.

When the first pair of wheels 24: enter-the control section B the coil 15 of the ramp relay L is energized by the following circuit:

Circuit number ten. From the track rail 2 of the control sect1on B, conductor 84, coil15, conductors 85 and. 86, armature 11 of the track relay 10 in its upper position, conductor 87, armature 19 of the ramp relay in its neutral position, conductors 88, 89 and 90 ,to the secondary of the transformer 21, conductors 91,

92, 93 and 94 to the track rail 1 and thence through the wheels 24 and the axle% back to the track rail 2. The coil 16 of the ramp relay 11 is also supplied with current from the transformer 22 of the, control section follows Circuit number eleven.

From the track rail 1, conductors 94 and 95, armature 13 of the track relay 10 in its upper position, conductor 96 to the secondary of the transformer 22 conductor 97 armature 14 conductors 98 and 99, coil 16,- conductors 100, 92, 93 and 94, back to the track rail 1.

The coils 15 and 16 of the ramp relay L are connected through two difi'erent transformers 21and 22 respectively "to the same source of alternating current, and the connections between said coils and said transits" . 3 (inctm's 91. (91M 9 EUR; 4, to time trnci;

Hi I ante}: the Mac/1152051011 C the truck pfltentiai es'tiabiis :c'mrmats is such 15113 the relz tiva time of the "xiii currani mm) Palm is; i

Q0, sevonda-r" .-i? than-an and: iiwnce the Wheels Q L and. the a like/ track mil 2. n the wheels and axle of (119 mm relay 1U 03'? said biock s g-iiion is siumi'cci, due to the so'mpza-iru'tivbif lqw resistance of said wimais and mic. and the zu'matm'es of said firm-k mm Wiii (imp. The dropping mi? time z-irmamre "ii of the 'trzurk rainy illiOil'UiJiH he circu'ir nun'fjer ten for energizing the coil 15., but i119 movement ut' the zunm/mrv 18 0f the mung: we L ha in the mmmtimr: set up the 1 7 nmnom' ii't-seh 1; That- 'ths c it imiv tn bu *I.l1(lflZ-ik i.

5?; there 1. 21 pan 0:

saviion.

piwziiiwn 11s rsimwn in Hw- SHIRE ihui r iuwey paisiti sn.

and the track mii '1 mmiiwi' Hm?! 1hr mining inie: n1

K. vommi (iQVlLH 1,

Lion {f is; iwccupiez'i the 1.1

' n Un'dmr H1050 Mandi.

, the train in the block 'sec A Q U 41m}; rain 1!) oi said block section and can armuture Le "The tmvk riii 013cm block section C. howe'v ei', is unergizei and tiie {)tll'biui cii'zuit number nine heir: before forth, which establishes high. difference of potentiai between i rzunp' 10C and the track mil 1 until 1:110 train first azitezs thv umti'ol mail-ion B, wil i'bu up in tin- Qnmi: way as mien the tmflic conditisus W me i uih as assumed abm'. Also, ii'uz; (fil'mlif numbsr ten for energizing the chi! mi 11v: Hump i'ciziy L \viil bv HM up. The ilz'i'ipping uf Hm :ufnmtnre 13 and H of tin? HHi-L 122M H) changes 'izhv qunnectionsa betum-n the "oil If Of'the ramp i'ei:

zoncim'y of" die miusi'u 'inul' tipphzzwu winfiion between the current fimfi in in the w lls 1153 and 16 03 said "amp yuhiy} L 1: di fi'ereni 131mm ldldl" the conditions bs- Hm: ZISQLHTHH; and: consequently, the airing: hm; 0i Hm rump 'i'ehiy L will move to the .ri 'nti ml of to tiufileft. To ,xphi' am-zumn that the poinrii oi the A i s ccmiiiui v of the 1': simmer 322 it is as iiiiiicat'cci in he 1 21w poim i v u? the Li 1; n" as: indimmd. Then, with H mm: in m busifion shomxiinhe clu'rmt iuv-x iiizuup 'ii either the'ciycui m1 sea 7 to hold its armature armature 67 in are in their lower position current will flow through the coil 16 in the opposite direction through the following circuit:

' Circuit number fourteen.

From the terminal of the secondary of the transformer 22 assumed to be positive at a given instant, conductor 96, armature 13 in its lower position, conductor conductor99, coil 16, conductors 100, 92, 93 and 94 to the track rail 1, conductors 94 93 and 106 armature 14 in its lower position, con- ,ductor 97 back to the other terminal of the transformer 22.

The reversal of the direction of flow of the current through the coil 16 as compared with the direction of thefiow ofcurrenj: in the. coil at any given instant causes the armatures of the ramp relayL to be moved to their right, as shown in the drawing, and the stick circuit for the coil 15 of said relay is as follows:

Circuit member fifteen.

From the track rail 2, conducor 84, coil 15, conductor 85, conductor 10], armature 18 in its righthand position, conductors 109, 89 and 90 to the secondary of the transformer 21, conductors 91,92, 93 and 94 to the track ..rail 1 and thence from the wheels 24. and the track rail 2.

the armature 17 of the right causes alowi difference of potential between the ramp R and the track rail 1 to be established according to the following circuit:

axle back to the e movement of ramp relay L- to the Uz'rcuit number sixteen.

From the ramp R, conductor 103, armature 17 in its righthand position, conductor 110, the low voltage tap a of the secondary 'of the transformer 20, and conductor 83 to the track rail 1.

Since the shoe 31- is in electrical contact with the ramp R at this time the low difference of potential sends current through the partial. circuits numbers seven and eight for the alternating current relays S and K.

The alternating current stop relay S is so constructed that a low difference of potential between the shoe 31 train will send sufficient current through it 63 in its upper position; Whereas the alternating current control relay K is so constructed that thislow difference of potential will not hold its its upperposition. The operating characteristic of these relays S and K, whereby they are responsive voltages, may beobtained in different ways, as will be appreciated by those skilled in the art of railway signaling; and for the 'purpose of understanding this invention it is deemed unnecessary to show and describe the construction of these alternating current and the frame of theto different relays S and K. When a 10W difference of potential exists between the ramp R and the track rail 1 the stop relay S is energized, since the armature 63 of its controlling relay a is raised; but the control relay K is deenergized, since the direct current holding circuit for said relay K number four is interrupted at the shoe and the armature 67 of its controlling relay K is dropped, as explained hereinbefore. Since the control relay K is deinergized, its armature drops and makes a break in the direct current holding circuit number relay, so that after the shoe 31 has left engagement with the ramp and the contact spring 34 has again made contact with the contact number 35, nevertheless this direct current holding circuit number four will be interrupted at the armature 4? and the control relay K will remain dei nergized until the next ramp is reached. hen the arnuv ture 46 of the control relay K drops, it interrupts the normally closed circuit number two for the control control device K into operation.

From the foregoing it can be seen that when the block section vE is occupied by a train, the train when it passcs the ramp R- will have the control device K dei nergized and set into operation, but the stop device S will remain cnergizedand will be incapable of affecting the movement of the train.

For the next traffic condition to be considered, assume eration is in the block section A and about to enter the control section B, asshown in the drawing; and that there is a train in the block section 0. The presence of the train in the block section C eriergizes the track relay 10 and causes its armatures to drop, and the dropping of the armature 12 of said track relay 10 interrupts the circuit number nine by which a high difference of potential is established between the ramp R and the track rail 1 before the train enters the control section B. Also since the train has not yet entered the control section B the coil 15 of the ramp relay L is not energized and the are in their neutral position, as shown in the drawing, in which the armature 17 opens a break in the circuits numbers thirteen and sixteen and prevents a high difference of potential from being established by' the transformer 20 D. Consequently, as the shoe 31 of the train engages the ramp B, there will be no difference of potential between that ramp R and the track rail 1, and both the stop relay S" and the track rail 1 prevents the alternating device K; and sets the that the train under consid armatures of said ramp relay' of the next control section 31 interrupts four of said riu'ant 1 91a m and K fmm wine;

d, :Wmrtm; amp ruin 53% is (131 M m l in; arm drum 2111C intel'rnp L) noamnlly (f3 fiwnii munim one '3 X Uuassmp device by (11 531:-

' :01) Cuwice mm sa it imu Minus v 16 xi'mn $131951 1 J1, n H

" v (min m J Q: and unmy these vim-mn- Haw-ii "m1 (Men wim at 1'! 7 h s ramp 11 i :7 g; haw an H m by the device infler somv 'ms, hmvvn H10 dmvmmw J til 1; :seuiion the prnssnw of? rain in said 1 01 a 12 0km mfi in mid ninth V misc mike! the 'izjliz'l {mini-(i than A, 50 ihat q gram would when me; ."me engages a stop device. 5 3% set into 511x250 cil'vmmtzmws H10 nppaiL-xl in the SGCHOH B and the Mock s00- 't'mu C new the mm? 361 block sodium the "m n may in-oufgbt m 2: m bv'fm-v thu WM niwt haw and rent from is to be 12m Home, wm h in the mi J A. (a.

jxlxhou the must of my inimtiom z: n and principlo. U1 7 Sim (0 11a v0 ii 1111641 00 lvcitvfi 11m?? mihu 1s 1; A i101 zxtvs, 1s: v 1. g siiem i0 nutomm' reontrch 1:35

i anointed with r and said low voltage source, and

one of the coils of said ling railway trains,

tuated to the position corresponding to the position to which it is actuated when said second succeeding block is not occupied, said circuit controller connecting said low voltage source to said ramp when operated to a position corresponding to the position to which it is operated when said second sueceeding block section is occupied, and an automatic t ain control mechanism carried by the train and responsive to said high andlow differences of potential. 2. In a system for automat cally controlin combination: a plurality of electrically isolated block sections, an insulated ramp associated with each section, a track relay and a source ofelectric current for the block section and constituting a normally closed track circuit therefor, high and low voltage sources of electric current associated with each ramp for creating high or low dilferences of potential between said rampv and the rails, a partial circuit controlled by the track relay of the next block section for establishing a high difl'erence of potential between said ramp and the track rails, a three-position relay associated with each ramp, the energization of one coil of said relay being controlled by the track relay of the next block section, coil of said ramp relay being controlled by the track relay of the second succeeding block section, the polarity of mentioned coil relatively to said first mentioned coil being different according to whether or not said track relay of said second succeeding block is energized or deenergized, a partial circuit controlled by one position of said ramp relay for electrically connecting said ramp and said high voltage source, another partial circuit controlled by the other' position of said ramp relay for electrically connecting said ramp automatic train control mechanism carried by the train and responsive to said high and low differences of potential.

In a system for automatically controlling railway trains. in combination: a trackway comprising electrically isolated block sections, a comparatively short control sec tion at the entrance to each block section and electrically isolated therefrom, an insulated ramp disposed near the entrance to each of.

said block sections, high and low voltage sources.of electrical energy associated with each ramp for creating high o low diflerences of potential between said ramp and the track rails, a three-position. relay associated with each ramp, the energization of relay being controlled by the presence of a train in the corresponding control section, the energization of the other coil of said relay being controlled by the presence of a train in the block track the energization of the other said second 1 ,aenecs second succeeding block section, the polarity of said second mentioned coil of said relay relatively to the polarity of said first mentioned coil being reversed when a train occupies said second succeeding block, a partial stick circuit for said coil of said three-position relay connected across the track rails of the corresponding control section, a circuit controller controlled by said three-position relay and connecting said high voltage source to said ramp when said relay is actuated to the position corresponding to the position to which it is actuated when said second succeeding block is not occupied, said circuit controller connecting said low voltage source to said ramp when operated to a position corresponding to the position to which it is operated when said second succeeding block section is occupied, and an automatic train control mechanism carried by the train and responsive to said high and low differences of potential.

4. In a system for automatically controlling railway trains, in combination: a'

. associated with each ramp for creating high or low differences of potential between said ramp and the track rails, a partial circuit controlled by the track relay of the next block section for establishing a high difference of potential between said ramp and the "track rails, a three-position relay associated with each ramn. the energization of one coil of said relay being controlled by the track relay of the next block section, a partial stick circuit for said coil of said threeposition relay connected across the track rails of the corres onding control section, the energization oi the other coil of said ramp relay being controlled by-the track relay of the second succeeding block section, the polarity of saidsecond mentioned coil relatively to said first mentioned coil being different according to whether or not said track relay of said second succeeding block is energized or detinergized, a partial circuit controlled by one position of said ramp relay for-electrically connecting said ramp and said high voltage source, another track, of imconditions of each impulse device,

pulse devices located. at intervals along the track and adapted to assume different controlling conditions, sources of electrical energy for producing the different controlling electromagnetic means normally disconnecting said sources from the corresponding impulse device, and traffic controlled means for controlling said electromagnetic means and selectively connecting said sources to the corresponding impulse device in accordance with the extent of unoccupied track in'advance of that impulse device.

6. In an automatic train control system, the combination with a railway track, of impulse devices located at intervals along the track and adapted to assume diliereilt controlling conditions, sources of current for producing the different controlling conditions of each impulse device, a normally deenergized polarized relay having contact fin gers which control selectively the connection between sa'd sources and the corresponding impulse device when the relay is energized,

the energization oi each relay and tion of movement of its contact fingers in accordance with the extent of unoccupied t 'a ck in advance of the corresponding impulse device, w

7. In an automatic train control system, in

combination: a track divided-into blocks; a

ramp associated with each block; partial circuits for determining the controlling condition of each ramp; a normally deencrgiaed polarized relay for controlling said partial circuits; means dependent on the presence of a. train adjacent to said ramp and upon the correspond ng block being unoccupied for causing energization oi said relay; and a cir cuit for each relay having its polarity dependent upon the pr sence or absence of a train in the block next in advance of the corresponding block.

8. In an automatic train control system in combination: a track divided into blocks having track circuits; an impulse device associated with each block; circuits for determining the controlling condition of each impulse device; polarized relay for controlling said circuits; an energizing circuit for said relay controlled by the t 'ack circuit oi.

the corresponding block; a maintaining circuit for said relay closed while a train is Su passing the corresponding impulse device;

and a circuit for each relay having its polarity controlled by the track circuit of the block next in advance of the corresponding block.

9. In an automatic train control system, the combination with a track divided into blocks having track circuits; of an impulse device associated with each block and adapted to assume: difierent controlling conditions, a normally denergized polarized relay for and trafiic controlled means for determining the (l11'8(- controlling each impulse device, an energizing circuit for each relay controlled by the track circuit of the corresponding block and a circuit for each relay having its polarity controlled by the track circuit of the block next in advance of the corres 'mnding block. 10. In an automatic train control system, in combination: a track divided into blocks having track iircuits; a comparatively short control section located at the entrance to each block and electrically isolated therefrom; an impulse device associated with each block; circuits for determining the controlling condition of each impulse device; a polarized relay "for controlling said circuits; means controlled by the track circuit oi? the corresponding block for preventing the energizetion of said relay when said block is occupied; a maintaining circuit for said relay dependent upon the preliminary cnergization thereof and lniving its contimility established by a pair oi. wheels and axle on the corresponding control section; and a circuit for controlling each relay having its polarity controlled by the track circuit of the block next in advance of the corresponding block. 11. In an automatic train control system, the combination with a track divided into blocks; of an impulse device associated with each block for transmitting impulses of diffcrent controlling characteristics to a passing train, impulse transmitting circuits associated with each, impulse device, a normally dci ncrgized polarized relay having contact fingers controlling said circuits, means for energizing said relay upon the approach of a train to each impulse device and for maintaining said relay energized while the train is passing that impulse device, means for preventing thev operation of said means when the mil-responding block is occupied. and means for detcrmiuimr the direction 0 i? movement of the contact fingers of each relay in accordance with traflic conditions in the block next in advance oi? the corresponding block.

12. In an automatic train control system. the combination with a railway track, of impulse devices located at intervals along the track, a polyphase relay having two windings for governing the controlling condition of each impulse device. a circuit for one winding of said relay controlled by the presence of a pair oi wheels and axle adjacent to the corres mnding impulse device, and the circuit for the other winding oi said relay having its polarity determined by traffic conditions for a. predetermined distance in advance of the corresponding impulse device.

13. In itllhlllOlllfllllO trr'n control system, the combination With'a' railroad track divided into blocks having track circuits, of a cmnparatively short control section at the entrance to each block and electrically isothe combination with lated therefrom, an impulse device associated with each block, normally open circuits for governing the controlling condition of each impulse device, normally denergized electromagnetic means for selectively controlling the continuity of said circuits, means controlled by the track circuit of the block next in advance for governing said electromagnetic means to determine the circuit controlled thereby, and a circuit associated with each electromagnetic means and con- ;trolled by the track circuit of the corre ponding block for determining the energiz'ation thereof.

14. In an automatic train control system, the combination with a railroad track divided into blocks having track circuits, of an impulse device associated with each block, normally open circuits for energizing each impulse device to cause it to assume different controlling conditions, a normally deenergized three-position relay for selectively controlling said circuits, means tending to cause energization of each relay and to maintain such energization While a train is passing the corresponding impulse device, said means being controlled by the track circuit of the corresponding block and beingeflective only when that block is not occupied, and means controlled by the track circuit of the block next in advance for determining theposition assumed by the moving elements of eachlrelay upon its energization.

, 15. In an automatic train control system,

a railway track, having track circuits, of impulse devices 10- train control system,

device located adjacent to the entrance endof each block, controlling circuits for each impulse device including sources of current of different electrical characteristics, a normally deenergized polarized relay for controlling said circuits,a circuit for each relay, means tending to cause energization of each relay upon passage of a train, and a p0le-changing device included in each last mentioned circuit and controlled by the track circuit of the. block next in advance of the corresponding block.

17. In an automatic train control system, the combination with a track divided into blocks having track circuits, of partial cir: cuits associated with each block for transmitting electrical impulses to a passing train, a normally denergized polarized relay having its polarity deter track circuit of the, block next in advan- 7c of the corresponding ble 2:. I

RICHARD C. LE KE.

relay for! controllingsald partial circuits, means cona track divided into i 

